Researchers say students who entered high school in 2007 with strong academic skills saw only a small improvement in their math, science and reading tests scores.

But students with weak academic skills performed worse and their high school graduation rates declined.

“I think we should have expected it,” says Susan Dynarski, a professor at U-M's Ford School of Public Policy, “You raise the bar. Some more people are going to slip under the bar.”

Dynarski says schools may still be learning how best to meet the merit curriculum standards. She hopes the data produced by the study will help the state and school districts direct resources to help low performing students.

The study was conducted by researchers from the University of Michigan, Michigan State University and the state of Michigan.